This invention relates to automotive steering systems in general and more particularly to a method and apparatus for reducing the effort required to steer an automobile at low speeds.
Assists for steering systems in automobiles are well known and, in the large automobiles produced by the United States auto makers in the past, came to be almost standard equipment. Although various types of assist systems were developed over the years, a hydraulic system was generally adopted in the industry. The hydraulic system used is one which operates whenever the engine is running although it is most useful in parking and at low speeds. The increased difficulty in steering at low speeds, such as when parking, comes about because of an increase in the friction between the road surface and the tire and because the wheels must be turned through a much larger angle than when operating on the road at higher speeds. Despite its convenience and popularity, power assisted steering is expensive to operate. In other words, it reduces gasoline mileage. In the past when gasoline supplies were plentiful and gasoline was inexpensive, this did not constitute a major problem. However, with increasing gasoline prices and with the tendency toward smaller cars, the inclusion of the conventional type power steering in such cars can be quite detrimental in the overall gasoline mileage. Furthermore, automobile makers, in order to achieve better mileage, are using smaller engines. The power required for power steering is taken from the engine and, if power steering of the conventional hydraulic type is to be used, a larger engine than might otherwise be required may need to be installed in the automobile, further reducing mileage.
Although the problem of steering a smaller car at low speeds and when parking is not as great as that with larger cars of the past, there is still a great deal of effort required by the driver in some instances. This can be a problem for less muscular drivers. It is thus apparent that a need exists for a steering assist system which does not consume large amounts of power, i.e., an assist system which will not appreciably decrease gasoline mileage and will not require a larger engine.